When she was a sophomore at Stanford in 2003, Holmes founded healthcare-technology company Theranos (a few months later, she dropped out to focus on the company). Today, she has a net worth of $4.6 billion.

Theranos is a $9 billion biotech company that has a new approach to blood testing. Its goal is to make clinical testing cheaper and faster.

Within a year she had filed a patent application for "Medical device for analyte monitoring and drug delivery," a wearable device that monitored patients' blood and administrated medicine.

As a sophomore, Holmes went to one of her professors, Channing Robertson, and told him: "Let's start a company." With his blessing, she founded Real-Time Cures, later changing the company's name to Theranos.

She dropped out of Stanford a semester later, working on Theranos in the basement of a college house.

For the first decade Holmes spent building her company, Theranos operated in stealth mode. She even took three former Theranos employees to court, where she claimed they had misused Theranos trade secrets.

Theranos develops blood tests that detect medical conditions, like cancer and high cholesterol. Instead of using a needle, Theranos is minimally invasive, and uses a pinprick in your finger to take just a couple drops of blood.

To date, Theranos has raised $92 million in VC funding from investors like Draper Fisher Jurvetson and Larry Ellison.

Theranos has drawn skepticism from the scientific community in part because Theranos is cagey about how its tests actually work.

According to The New Yorker, Holmes "can quote Jane Austen by heart, [but] no longer devotes time to novels or friends, doesn't date, doesn't own a television, and hasn't taken a vacation in 10 years ... She is a vegan, and several times a day she drinks a pulverized concoction of cucumber, parsley, kale, spinach, romaine lettuce, and celery."